Document Detail


Change of potassium current density in rabbit corneal epithelial cells during maturation and cellular senescence.
MedLine Citation:
PMID:  16440065     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: Voltage-gated potassium (K+) channels may participate in cellular developmental regulation, including cell differentiation, proliferation and apoptosis. This study investigated the change of K + current densities in corneal epithelial cells during maturation and cellular senescence. METHODS: New Zealand white rabbits were divided into three age groups: newborn (<or= 7 days old, n = 18); young (8-12 weeks old, n = 59); and adult (20-28 weeks old, n = 16). Rabbit corneal epithelial cells were subdivided into the following three groups: small cells with capacitance < 6.0 pF; medium cells with capacitance 6.0-10.0 pF; and large cells with capacitance > 10.0 pF. Using a whole-cell clamp technique, K+ current was recorded and current densities were calculated. Differences in K+ current densities among newborn, young and adult rabbits, as well as differences among small, medium and large cells, were analyzed. RESULTS: We delineated two types of cells manifesting different amplitudes of depolarization-activated K+ outward currents. The averaged current density of type 1 response cells was significantly larger than that of type 2 cells in newborn, young, and adult groups. For newborn epithelial cells, the depolarization-gated outward K+ current density decreased from small to medium to large cells (p = 0.049, at a membrane potential of 140 mV). A similar pattern of change in current density was also delineated for these cell sizes in young and adult rabbit corneal cells (p < 0.001 for both young and adult rabbits). An increase in depolarization-gated outward K+ current density was also delineated from newborn to young to adult rabbits (p < 0.001, p < 0.001 and p < 0.006 for small, medium and large cells, respectively, at a membrane potential of 140 mV). CONCLUSIONS: Corneal epithelial cells expressed K+ channel densities that were distinct from basal to superficial cells and from newborn to adult rabbits.
Authors:
Shu-Wen Chang; Gwo-Jyh Chang; Ming-Jai Su
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of the Formosan Medical Association = Taiwan yi zhi     Volume:  105     ISSN:  0929-6646     ISO Abbreviation:  J. Formos. Med. Assoc.     Publication Date:  2006 Jan 
Date Detail:
Created Date:  2006-01-27     Completed Date:  2006-02-28     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9214933     Medline TA:  J Formos Med Assoc     Country:  China    
Other Details:
Languages:  eng     Pagination:  7-16     Citation Subset:  IM    
Affiliation:
Department of Ophthalmology, Far Eastern Memorial Hospital, Department of Ophthalmology, National Taiwan University Hospital, Taipei, Taiwan, R.O.C.
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MeSH Terms
Descriptor/Qualifier:
Animals
Cell Aging / physiology*
Epithelial Cells / metabolism*
Epithelium, Corneal / cytology,  metabolism*
Potassium Channels, Voltage-Gated / metabolism*
Rabbits
Chemical
Reg. No./Substance:
0/Potassium Channels, Voltage-Gated

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